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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 27 November 2017 by John Abraham

The United States Global Change Research Program recently released a report on the science of climate change and its causes. The report is available for anyone to read; it was prepared by top scientists, and it gives an overview of the most up to date science.

If you want to understand climate change and a single document that summarizes what we know, this is your chance. This report is complete, readily understandable, and accessible. It discusses what we know, how we know it, how confident we are, and how likely certain events are to happen if we continue on our business-as-usual path.

To summarize, our Earth has warmed nearly 2°F (1°C) since the beginning of the 20th century. Today’s Earth is the warmest it has ever been in the history of modern civilization.

Global average surface temperatures over the past 1,700 years. Illustration: United States Global Change Research Program

While the planet has warmed, the climate and the Earth’s environment has responded. We are observing heating of the atmosphere, oceans, and the Earth’s surface. Glaciers are melting at an alarming rate. Snow cover is decreasing and we are experiencing increased water scarcity, particularly in parts of the world that rely on snowmelt for water.

The amount of ice is decreasing. In particular, the ice that floats atop waters in the Arctic have decreased significantly since measurements began. As a result of melting land ice and thermal expansion, sea levels are rising. Oceans have risen, on average, 7–8 inches. In some places, the rise has been much more. Astonishingly, half of the total rise has occurred in the last 30 years. Currently, oceans are rising faster than any point in time in the last ~3,000 years. Not only that, the ocean rise is causing city flooding to accelerate.

According to the report, seal levels will likely rise somewhere between 1–4 feet by the end of the century, but increases up to 8 feet can’t be ruled out (~2.5 meters). For context, approximately 150 million people around the world live within one meter of current sea level.

If you live away from the shores, you are not immune to the impacts of climate change. The report delves into the increases in extreme weather. For instance, heavy rainfall is increasing across the United States as well as globally. These increases will continue into the future and they are already leading to more severe flooding. The prediction that scientists made that wet areas will become wetter is turning out to be true.

There are more extreme heatwaves as well. Not only are we seeing more heat waves (and severe droughts), but in the next few decades, the authors predict temperatures will rise by ~2.5°F (~1.5°C) in the United States. This is an enormous change in temperature that will reshape the country. Similar changes are occurring and will occur in other countries.

Any one person has little effect on the course of AGW. You might equally well say: "What are the chances of Obama's rolling back the rise of the sea?"

Actually, the USA's C02 output has levelled off. Sooner or later, perhaps later than is wise, public opinion in the USA will consider it to be a both undesirable and significant. Lyndon Johnson was warned of this phenomenon in the 1960s, and of course he blew it off. As the cost of low carbon alternatives falls and concern over the consequences of higher carbon sources grows we may reach a point here the curves cross and the former replaces the latter.

If one wants to focus on a few figureheads, then do so on the monarchs and despots who need not concern themselves with popular sentiment, and who are pumping out cheap fossils fuel.

That would be the leaders of Saudi Arabia, Kuwait, Iran, Nigeria, Mexico and (once their wells are taken over by China & Russia) Venezuela. That's where the oil comes from, and crucially this is the low cost, price-setting oil. Were these producers to say "hey ya know what, we've already produced 2/3 of the oil ever used and we're concerned about the global C02 budget, so next years we're cutting production by 50%, and by half again the year after". The remaining oil has a far higher cost of production, and can't be drawn out fast enough to supply today's demand without massive investment, if at all. Whether by price or supply, oil demand would plummet.

Trump?? A distraction, and a minor one. He has very limited control over some barely break-even rapidly depleting oil (US shale). He can maybe nudge the needle a tad, but more than the slightest nudge which throws people out of work and his job goes next.

"He has very limited control over some barely break-even rapidly depleting oil (US shale)."

As much as I would l like to hear that this is the case, my understanding is that the "tight oil" industry continually finds ways to reduce costs by more efficient fracture stimulation methods. Do you have any backup for your statement above regarding "rapidly depleting shale oil"?

I remember years ago when horizontal fracing (where did the "K" come from in fracture stimulation?) has opened up tight natural gas reserves. Everyone said it would be impossible to apply this technology to oil. We all know what happened there.

"As the cost of low carbon alternatives falls and concern over the consequences of higher carbon sources grows we may reach a point here the curves cross and the former replaces the latter."

This is a very good point, and probably true.

Humans process information and make decisions based on mentally weighing costs, benefits and probabilities of these things happening, according to psychological research. I dont see that climate issue would be different. I dont know when the crossover point would come to cause massive change, but it may not be far away.

The important thing is to ensure people have good information on which to base such decisions, as opposed to climate denialist junk.

Norris and others, fracking is scraping the bottom of the barrel in global oil shale terms. However America has over half the worlds shale oil reserves, so its not going to run out of shale oil anytime soon, described here.

Norris you are an eternal optimist on technology and eternal pessimist on scientific modelling. Fracking has found more efficient technologies but there are limits to the process. Consider in comparison, conventional oil extraction went through a process of rapid innovation, but hasn't changed much now in decades. As many wells are half used up extraction gets more expensive. Oil from fracking is already expensive and its not going to magically become cheaper and cheaper forever. There are limits to what technology can do.

The following is an interesting summary on oil situation globally and in America here.

This is interesting in particular:

"That said, the Rystad report also illustrates why it’s critical for the U.S. to focus on developing other, renewable forms of energy. “Rystad Energy now estimates total global oil reserves at 2092 billion barrels, or 70 times the current production rate of about 30 billion barrels of crude oil per year, the report reads. “This data confirms that there is a relatively limited amount of recoverable oil left on the planet. With the global car-park possibly doubling from 1 billion to 2 billion cars over the next 30 years, it becomes very clear that oil alone cannot satisfy the growing need for individual transport.”

Norris actually you are more an an eternal optimist on fossil fuel extraction technology and eternal pessimist on renewable energy technology. And this contradiction makes no sense at all, on the basis of actual evidence, and is clear example of confirmation bias. Both technologies have potential for development, and if anything newer technologies like renewable energy have more room for innovation at this stage than oil extraction, simply because they are so new.

nigelj, NorrisMThe need to rapidly transition from burning fossil fuels to much more sustainable and less damaging ways of obtaining personal benefit has been well understood since the 1960s.

The fact that research effort is still being put into fossil fuel for burning rather than have that effort be on improvement and expansion of better ways of behaving is Proof that the current socio-polotical-economic-environmental games played by humans are fatally flawed.

The major flaws are 'pursuits of Private Interests' winning the ability to compromise the 'Global Public Interest in developing a lasting better future for humanity'. The focus is on people pursuing the best possible present for themselves any way they can get away with. Those Private Interests compromise the environment and the future whenever they are Balanced with concern for the environment or Others.

In previous postings I indicated that I personally have been moved by the two papers by Derek Abbot suggesting a thermal solar thermal/hydrogen solution which would require a continental HVDC system. I had hoped we could get a discussion going on the benefits of PV solar versus thermal solar (and whether we should be focussing on electric cars versus hydrogen) based upon those 2010 papers but my understanding is that such a discussion is beyond the focus of this website. As well, we again face political reality in the US.

Norris @11, I agree such a discussion is interesting, and I think it's all related to climate science. This website did do an article on electric cars.

Just briefly, regarding PV solar versus thermal solar. IMO they are both good systems. It may not be either / or. Thermal solar suits large centralised instillations, and pv solar suits roof top arrays, and poor third world countries.

Regarding hydrogen fuel cell cars versus batteries. They are both good cars, and hydrogen fuel cell cars have been on the market since about 2014, and I'm reasonably sure Honda make one. From a technical point of view, they are very roughly equal abilities, although batteries are a bit more efficient ultimately. However I would welcome more information and discussion and my knowledge is limited.

The real trouble is hydrogen fuel cells absolutely require a network of charging stations and there are currently very few, and nobody will provide then until their are sufficient cars, and nobody will buy the cars until theres a full network of rechghaging stations, so its a stale mate situation. Uptake of hydrogen cars has been very slow, so it looks like a losing technology I'm afraid. Battery cars can just be plugged into a wall socket, so this is very flexible as you are not as reliant on recharging stations. Things have to be user friendly.

Hydrogen is a very ephemeral fuel because of its volatility. Any distributing pipeline and containers must be super-tight. Typical infrastructures, e.g. those used for natural gas, would allow to much fugitive loss due to leaks.

Related is the problem of vehicle safety while transporting a big tank. The tank must be super-tight and armoured - stronger than e.g. LPG tank. This adds the extra weight to carry by the vehicle.

Yes making hydrogen safe is going to be expensive. This may partly explain the high cost of hydrogen fuel cell cars (about $60,000 US). This is more than basic electric cars.

There might be a psychological factor with hydrogen fuel cell cars. People just may not want to be sitting on a tank of hydrogen. Of course the fact they are on the market suggests they are well safety tested and probably have crash sensors etc, but people will still be cautious.

I read somewhere the hydrogen tanks in cars are some form of composite carbon fibre, possibly to maximise strength and minimise weight. I dont know how much minimised it is in relation to the weight of lithium batteries.

I think battery cars make more sense right now. The main advantage of hydrogen cars has been range, but batteries are improving. Hydrogen cars use water as the ultimate source of hydrogen, so this is an abundant resource, but the overall fuel cell technology and recharging requirements doesnt look practical right now.

Yes hydrogen fuel cell powered trucks are a scary thought. Please appreciate I'm just trying to be a bit open minded as well on the issue. Apparently the tanks in the Honda hydrogen fuel cell car have impact sensors that shut off the fuel supply, and very rigid strong tanks. On the other hand, if this failed on a truck, it would be totally catastrophic.

My instinct has always been that hydrogen fuel cells are a dead end idea, unless we run out of materials for batteries.

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